Building a mathematical model of vacuum arc interruption-parameter optimization

Design of new vacuum interrupters and performance evaluation of existing devices can be greatly enhanced by using mathematical models of vacuum arc interruption. The so-called transition model of Andrews and Varey (1971) has been augmented by Glinkowski et al. to include nonuniform distribution of plasma density and breakdown criteria. The model contains four critical parameters, constants, that have to be determined for a particular device and external electrical circuit conditions. This paper describes a numerical approach to determine the optimum values of the four parameters from the measured test data of voltage and current of the vacuum switch in the vicinity of current zero. Although the approach is purely mathematical its results provide an interesting, new insight to the physics of the arc plasma and possible phenomena occurring during interruption.